Long term evolution (“LTE”) of the Third Generation Partnership Project (“3GPP”), also referred to as 3GPP LTE, refers to research and development involving the 3GPP LTE Release 8 and beyond, which is the name generally used to describe an ongoing effort across the industry aimed at identifying technologies and capabilities that can improve systems such as the universal mobile telecommunication system (“UMTS”). The notation “LTE-A” is generally used in the industry to refer to further advancements in LTE. The goals of this broadly based project include improving communication efficiency, lowering costs, improving services, making use of new spectrum opportunities, and achieving better integration with other open standards.
The evolved universal terrestrial radio access network (“E-UTRAN”) in 3GPP includes base stations providing user plane (including packet data convergence protocol/radio link control/media access control/physical (“PDCP/RLC/MAC/PHY”) sublayers) and control plane (including a radio resource control (“RRC”) sublayer) protocol terminations towards wireless communication devices such as cellular telephones. A wireless communication device or terminal is generally known as user equipment (also referred to as “UE”). A base station is an entity of a communication network often referred to as a Node B or an NB. Particularly in the E-UTRAN, an “evolved” base station is referred to as an eNodeB or an eNB. For details about the overall architecture of the E-UTRAN, see 3GPP Technical Specification (“TS”) 36.300 v8.7.0 (2008-12), which is incorporated herein by reference. For details of the communication or radio resource control management, see 3GPP TS 25.331 v.9.1.0 (2009-12) and 3GPP TS 36.331 v.9.1.0 (2009-12), which are incorporated herein by reference.
As wireless radio communication systems such as cellular telephone, satellite, and microwave communication systems become widely deployed and continue to attract a growing number of users, there is a pressing need to accommodate efficiently a large and variable number of communication devices that transmit an increasing quantity of data within a fixed spectral allocation and limited transmitter power levels. The increased quantity of data is a consequence of wireless communication devices transmitting video information and surfing the Internet, as well as performing ordinary voice communications. Such processes are generally performed while accommodating substantially simultaneous operation of a large number of wireless communication devices.
At present, there are mainly two kinds of wireless communication system or network architectures, centralized and distributed. A centralized communication network can be taken as a conventional infrastructure-based cellular communication network whereas an ad-hoc communication network exemplifies a distributed communication network. In a centralized cellular communication network (also referred to as a primary communication system), a wireless communication device such as user equipment communicates with another wireless communication device such as user equipment through a base station, which is also referred to as primary spectrum usage. However in an ad-hoc communication network (also referred to as a secondary communication system), the user equipment communicates directly with another user equipment (or through a relay), which is also referred to as secondary spectrum usage. In the primary communication system, traffic goes through a centralized controller such as a base station even if the source and destination user equipment close to each other. The main benefit of such operation is easy communication resource and interference control, but the obvious drawback is inefficient communication resource utilization. For example, significantly more communication resources are generally required for cellular communications (or a cellular communication mode) compared to a device-to-device (“D2D”) communications (or D2D communication mode) when the user equipment are relatively close.
To achieve better system throughput, a future radio communication system or network will likely operate in multiple communication modes. Such a hybrid operation can provide high system performance due to spectrum communication resource sharing by user equipment operating in cellular and D2D communication modes, but interference between the primary and secondary communication systems becomes an issue when cellular spectrum is reused by user equipment operating in the D2D communication mode. Since the user equipment can operate in both communication modes, interference associated with the user equipment operable in the communication modes should be resolved. Thus, there is need for an improved system and method that can addresses interference issues for wireless communication devices operable in primary and secondary communication systems that avoids the deficiencies of current communication systems.